Electromagnets have been used to oscillate tuning forks to form oscillators and compact narrow bank audio filters. More recently these oscillators have been used in optical applications, such as with laser beam choppers and optical fibre scanning.
Existing systems, however, have a number of drawbacks. For example, one optical oscillator includes an optical fibre attached to the tuning fork, to provide a simple and efficient integrated optical scanner. In these existing systems, a pair of electromagnets is used to vibrate the tines of the tuning fork, with the optical fibre attached to one of the tines. Typically the electromagnets are located either between the tines or disposed on opposite sides of the fork. However, owing to the size of the electromagnets, a lower limit is imposed on the overall size of the scanner (i.e. fork and electromagnets) and if, for example, an outside diameter of less than about 7 mm is required, such as in endoscope applications, very little space is left for deflection of the attached fibre.